1. Field of the Invention
The present invention relates to a battery chamber structure suitable for use in an electronic device such as a mobile communication device.
2. Description of Related Art
Recently, the use of portable information terminals such as various mobile communication media has been popularized at high rate. In such portable information terminal, a real time information is obtained by transmitting and receiving an information through the electronic mail or a facsimile by utilizing a telephone circuit or a portable radio equipment.
Conventionally, a battery chamber having a structure such as shown in FIG. 6 has been employed in such portable information terminal.
Describing the battery chamber structure 61 of this portable information terminal with reference to FIG. 6, the battery chamber structure 61 is equipped with a casing 62, a cover member 63 and a lock piece 64. The casing 62 is molded with a synthetic resin and has substantially a rectangular parallelepiped configuration. The casing 62 houses a communication equipment (not shown), etc., and has a battery chamber 66 for holding a battery B by pressing it by a spring terminal (negative terminal) 65 in the form of a frustum of a cone to a fixed terminal (positive terminal). A recess 67 is formed in the casing 62 on the side of the spring terminal 65 thereof. The recess 67 is opened in an upper surface portion 62a of the casing and, when the battery chamber 66 is closed by the cover member 63, communicates with a recess (not shown) formed in an inner surface of the cover member 63. The battery chamber 66 includes a back face portion 66a, left and right side face portions 66b (only one of them is shown) and a bottom face portion 66c and is formed by partially cutting away the upper surface portion 62a and a front surface portion 62b of the casing 62. A fitting portion 68 which extends in parallel to an axis direction of the battery B is formed in an edge portion of an opening of the bottom face portion 66c. The cover member 63 is L shape in cross section and is fitted in the fitting portion 68 of the casing 62 such that it can reciprocate along the fitting portion 68. The lock piece 64 can reciprocate in a space defined by the recess 67 of the casing 62 and the recess (not shown) of the cover member 63.
In this battery chamber structure, in order to load the battery B in the battery chamber 66, the fitting state between the casing 62 and the cover 63 is released to open the battery chamber 66 and the battery B is resiliently fitted between the spring terminal 65 and the fixed terminal (not shown). On the other hand, in order to remove the battery B from the battery chamber 66, the fitting state between the casing 62 and the cover 63 is released to open the battery chamber 66 and the spring terminal 65 is compressed to allow the battery B to be derived from the battery chamber 66 freely.
With the recent reduction of size and weight of an electronic device such as portable information terminal, the electronic device equipped with the battery chamber structure of this type is frequently carried in a bag of a user or in a pocket of his clothes. Therefore, there may be a case where such electronic device is erroneously dropped dependent on a state of use or dropped from the bag or the pocket dependent on an attitude of the user. As mentioned, the battery B is resiliently held between the spring terminal 65 and the fixed terminal (not shown). Therefore, when the electronic device is erroneously dropped and the battery B in the battery chamber 66 is shocked thereby, the shock power may move the battery B in a direction in which the spring terminal 65 is compressed and may be separated from the fixed terminal (not shown). In such case, a power is not supplied to electronic parts (not shown) within the casing 62, resulting in a degraded reliability in power supply.
In order to solve such problem, it may be considered to increase the spring constant of the spring terminal 65 to thereby rigidly support the battery B within the battery chamber 66. In such case, however, the insertion and/or replacement of the battery B with respect to the battery chamber 66 becomes difficult.
Incidentally, a battery chamber structure of an electronic device disclosed in Japanese Patent Application Laid-open No. Hei 9-259850 or Hei 9-306450 does not solve the above mentioned problem.